This invention relates in general wheelchairs and, in particular, to wheelchair accessories. Most particularly, the invention relates to a wheel lock for wheelchairs.
Wheelchairs are well known forms of transportation that increase the mobility of the physically impaired. Wheelchairs are typically relatively small, single-person conveyances that generally comprise a seat supported by a frame which, in turn, is supported by two opposed drive wheels and two front casters. Many manual wheelchairs are provided with wheel locks that are designed be actuated to engage the rear, drive wheels so that the wheels are prevented from rotating. Wheel locks are particularly useful to prevent the wheelchair from rolling on a sloped surface or to immobilize the wheelchair while the wheelchair user is accessing or exiting the wheelchair.
Conventional wheel locks usually comprise a contact bar pivotally mounted so that it can be swung into engagement with the resilient rear drive wheel on a manual wheelchair. The pivoting action is often adapted with a spring or other similar biasing device to urge the contact bar into contact with the tire during engagement. The wheel lock mechanism is usually mounted on the wheelchair frame, using a two-piece frame clamp to which is bolted a separate wheel lock mounting bracket. The conventional wheel lock mounting bracket further includes an actuation lever.
Despite the benefits of known wheelchair locking mechanisms, it would be advantageous if there could be developed a wheelchair lock that is simple and relatively inexpensive to manufacture. Wheelchair wheel locks are mounted on each side of the wheelchair, so that a left hand wheel lock unit and a right hand wheel lock unit are required for each wheelchair, and this necessitates an inventory of numerous parts. It would be beneficial if the number of individual parts required for assembly of the left hand and right hand wheelchair wheel locks could be reduced.
The above objects as well as other objects not specifically enumerated are achieved by a wheel lock for a wheelchair, where the wheelchair has a rear drive wheel. The wheel lock includes a housing adapted to be mounted on the wheelchair. The housing has two pivot points spaced apart in a forward/rearward direction. A wheel contact arm has a pivot shaft pivotally mounted about one of the pivot points. The wheel contact arm has a wheel engagement edge adapted to contact the rear drive wheel. The wheel lock also includes an actuation lever pivotally mounted about the other of the pivot points, and a linkage connecting the wheel contact arm and the actuation lever. The housing, the pivot shaft, the actuation lever and the linkage form a four bar linkage. Pivoting of the actuation lever causes pivoting of the wheel contact arm to engage the wheel contact edge with the rear drive wheel.
According to this invention, there is also provided a wheelchair including a frame, a rear drive wheel, and a wheel lock. The wheel lock includes a housing mounted on the wheelchair, the housing having two pivot points spaced apart in a forward/rearward direction. A wheel contact arm has a pivot shaft pivotally mounted about one of the pivot points. The wheel contact arm has a wheel engagement edge adapted to contact the rear drive wheel. The wheel lock also includes an actuation lever pivotally mounted about the other of the pivot points, and a linkage connecting the wheel contact arm and the actuation lever. The housing, the pivot shaft, the actuation lever and the linkage form a four bar linkage. Pivoting of the actuation lever causes pivoting of the wheel contact arm to engage the wheel contact edge with the rear drive wheel.
According to this invention, there is also provided a wheelchair including a frame, a rear drive wheel, a left hand wheel lock and a right hand wheel lock. Each wheel lock includes a housing mounted on the wheelchair, the housing having two pivot points spaced apart in a forward/rearward direction. A wheel contact arm has a pivot shaft pivotally mounted about one of the pivot points. The wheel contact arm has a wheel engagement edge adapted to contact the rear drive wheel. The wheel lock also includes an actuation lever pivotally mounted about the other of the pivot points, and a linkage connecting the wheel contact arm and the actuation lever. The housing, the pivot shaft, the actuation lever and the linkage form a four bar linkage. Pivoting of the actuation lever causes pivoting of the wheel contact arm to engage the wheel contact edge with the rear drive wheel.
Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiments, when read in light of the accompanying drawings.